The present invention relates to a supporting mechanism, and more particularly to a supporting mechanism for a pressure thermoforming machine.
As showing in FIG. 4, a conventional pressure thermoforming machine generally includes a lower bracket (b) and an upper bracket (a) corresponding to the lower bracket (b). A lower molding half (f) moveably driven by a lower cylinder (e) is mounted on the lower bracket (b); while an upper molding half (d) moveably driven by an upper cylinder (c) is mounted on the upper bracket (a). The upper and lower molding halves (d, f) are moved toward each other for forming an article therebetween, and moved away from each other for releasing the formed article therefrom.
Once the upper and lower molding halves (d, f) are closed, a molding cavity defined therebetween is undergone a vacuuming process such that a molten material can adequately flow to completely fill the cavity. In case of an asymmetric molding cavity, after the molten material filled in the cavity, an unbalanced situation of the lower molding half (f) will be encountered since the lower molding half (f) is simply supported by a piston of the lower cylinder (e). As a result, the unbalanced situation of the lower molding half (f) will cause separation of the upper and lower molding halves (d, f) such that the article formed therebetween will become defective, for example, a gap generated therefore will cause a variation of dimension of the article.
It is an object of this invention is to provide a supporting mechanism for a pressure thermoforming machine in which a lower molding half is adequately supported to prevent any unbalanced situation during molding process.
In order to achieve the object set forth, a pressure thermoforming machine in accordance with the present invention comprises a lower bracket having a molding half moveably supported thereon. An upper bracket is securely connected to the lower bracket. An upper molding half is moveably supported thereon. Driving blocks are moveably and oppositely mounted on the lower bracket. Each driving block includes an inclined surface and the driving blocks are moveably interconnected such that the driving blocks move toward and away from each other simultaneously. Rollers are mounted on the lower molding half with respect to the inclined surface of the driving block such that the lower molding half moves upward when the driving blocks move toward each other, and lower downward when the driving blocks move away from each other.